Developing his career in preparation for his retirement, Castaignède became a rugby union columnist for The Guardian, a television pundit for Canal+[1] and occasionally ITV Sport, and started an association and occasional work with French banking group Société Générale.[2] On 10 May 2007, despite offers to return to France with various clubs, Castaignède announced his retirement from the sport after the 2007 Rugby World Cup in September, choosing to pursue a career in banking in London.[3]